Method and Apparatus for Reducing the Interferences Between a Wideband Device and a Narrowband Interferer

ABSTRACT

A method includes a main interference reduction mode for reducing the interference generated by a wideband device toward a narrowband device. The main interference reduction mode is performed within the wideband device and includes at least one of detecting an emission from and a reception performed by the narrowband device. A group of at least one sub-carrier having frequencies interfering with frequencies used by the narrowband device is determined from the detection step. The bits of the punctured stream that correspond to the information carried by the interfering sub-carriers of the group are determined and processed so that the processed bits are mapped into a reference symbol having an amplitude within a threshold of zero.

The invention relates to the wireless communication systems, and moreparticularly to the processing of interferences within differentwireless communication apparatuses.

A non-limitative application of the invention is directed to devicesoperating according to the Ultra Wide Band (UWB) standard based on OFDM(Orthogonal Frequency-Division Multiplexing), called MBOA (MultibandOFDM Alliance), which can generate interferences towards a WIMAX devicewhich is a fix wireless device (Worldwide Interoperability for MicrowaveAccess). Such a WIMAX device operates for example with a band width of20 MHz at a central frequency of 3.5 GHz, whereas the frequency band ofthe MBOA system lies between 3.1 and 5.0 GHz.

Wireless personal area networks based on OFDM and UWB technologies likethe MBOA standard will directly interfere to narrowband interferer whichare close to such wide band devices. At present, no specificinterference mitigation techniques are implemented in the UWB standardbased on OFDM (MBOA).

Orthogonal frequency-Division Multiplexing (OFDM) is a method of digitalmodulation in which a signal is split into several narrowband channels(sub-carriers) at different frequencies. In order to avoid in-bandspectral interference, WO 2005/006698 (INTEL) proposes to puncture, i.e.remove, selected sub-carriers. More precisely, this puncturing is made,taking into account channel knowledge, after the OFDM modulation in thetransmitter, whereas a depuncturing is performed in the receiver beforethe OFDM demodulator. Because of the puncturing of some sub-carriers,the size of the encoded block of data which will be convert into OFDMsymbols, has to be reduced. Consequently, not only the software of theMAC (“Medium Access Control”) entity of the UWB device must be modifiedto take into account this size reduction of the data block, but thereceiver needs to know the actual used puncturing scheme, for examplethrough the transfer of control information from the transmitting deviceto receiving device, leading to an interruption of the transmission ofthe useful data between the transmitting device and the receivingdevice.

The invention intends to solve this problem.

An aim of the invention is to minimise the interference to an in-bandvictim device without needing any modification in the control layer, forexample the MAC layer, of the wide band device, and without needing anyadditional communication overhead on the air.

Another aim of the invention is to propose a solution which permits acommunication between devices implementing the invention and devices notimplementing the invention.

According to an aspect of the invention, it is thus proposed a methodfor reducing the interferences between a main device, for example a UWBMBOA device, adapted to transmit information on sub-carriers havingfrequencies belonging to a main band of frequencies and at least oneauxiliary device, for example a WIMAX device, adapted to emit and/orreceive information within an auxiliary band of frequencies, saidauxiliary band being narrower than said main band and included withinsaid main band. The information transmitted on said sub-carriers by saidman device are issued from symbols obtained by a mapping of a puncturedscheme of bits according to a modulation mapping scheme.

According to this aspect of the invention, said method comprises a maininterference reduction mode for reducing the interference generated bysaid main device towards said auxiliary device. Said main interferencereduction mode is performed within said main device and includes:

-   -   detecting an emission from and/or reception performed by said        auxiliary device,    -   determining from said detection step a group of at least one        sub-carrier having frequencies interfering with said auxiliary        band of frequencies,    -   determining the bits of said punctured stream which correspond        to the information carried by said interfering sub-carriers of        said group, and    -   processing said determined bits such that said processed bits        are mapped into a reference symbol having an amplitude equal or        close to zero.

Thus, after OFDM modulation of such a reference symbol, thecorresponding sub-carrier is not or almost not modulated. In otherwords, no energy or almost no energy is transmitted on this sub-carrierso that the interference will be minimised if not eliminated becausethis interfering sub-carriers have been notched out or almost notchedout.

However, there is no modification of the size of the data block and nomodification in the software of the MAC layer. In fact, the sub-carriernotching according to this aspect of the invention leads to a loss oftransmitted information. In other words, on the receiving device pointof view, the receiver will consider that he does not receive anyinformation or that he receives a high level of noise. Accordingly,after OFDM demodulation and demapping, the corresponding soft bits willhave a very low reliability leading to a appropriate correction duringthe decoding step.

Further there is no need to inform the receiving terminal. Thus themethod according to this aspect of the invention can be considered asbeing a blind or seamless method of sub-carrier notching.

As an example, a 20 MHz narrow band carrier which can be the width ofthe auxiliary band of the auxiliary device (for example the WIMAXdevice) corresponds to only 1.3% of the used UWB spectrum of a MBOAbased device and corresponds for example to an interfering sub-carriergroup of 5 or 7 sub-carriers. And this leads to a small amount of losttransmitted information which does not affect the performance of thedevice.

More generally, the larger the width of the auxiliary band of theauxiliary device is, the more the number of interfering sub-carriers tobe notched out is important and the more the consequence on thecommunication performance is important. Accordingly, the man skilled inthe art will be able to decide whether or not the invention can beapplied for a given narrowband interferer depending on the desiredcommunication performance.

However, narrow band interferers having band width smaller than 5 to 10%of the main band width (the band width of the main device) are perfectlycompatible with this aspect of the invention.

Said reference symbol is preferably chosen within a group of severalreference symbols having respectively different amplitudes, eachamplitude being equal or close to zero. For example, this referencesymbol or neutral symbol can be chosen among a set of for example fourvalues. The corresponding sub-carriers could then be controlled in theirtransmit power. The lowest value of the reference symbol wouldcompletely notch out the carrier whereas higher values would onlyattenuate the related sub-carriers. By doing so, some part of thecancelled information could still be transmitted and thus a slideimprovement of the communication performance could be reached. Further,choosing a reference symbol having a value close to zero but not equalto zero would render the implementation of the radio frequency stage ofthe apparatus easier than with a reference symbol having a zero value.

According to an embodiment of the invention, the processing step of saiddetermined bits comprises associating a control indication to eachdetermined bit and bits associated with said control indication aremapped into said reference symbol.

For example, said processing step comprises associating a control bit toeach bit of said punctured stream, said control bit having a firstlogical value corresponding to said control indication or a secondlogical value. The bits associated with control bits having said secondlogical value are mapped into their corresponding symbols in accordancewith said modulation mapping scheme, whereas the bits associated withcontrol bits having said first logical value are mapped into saidreference symbol.

Whereas the wide band device generates interference towards the narrowband interferer, there is also an in-band interference generated by thenarrowband interferer in the wide band device even if it is lessimportant. According to another embodiment of the invention, it is thuspossible to minimise also such interferences generated by the narrowbandinterferer towards the wide band device.

More precisely, according to such an embodiment, in which said maindevice is also adapted to receive information carried by saidsub-carriers and to perform a reception processing including determiningreceived symbols from the received information and demapping saidreceived symbol for providing a punctured stream of soft bits (each softbit having a sign representative of the estimation of the logical valueof the corresponding bit and a magnitude representative of theconfidence in said estimation), said method further comprises anauxiliary interference reduction mode for reducing the interferencegenerated by said auxiliary device (the narrow band device) toward saidmain device. Said auxiliary interference reduction mode is performedwithin said main device and includes replacing the soft bitscorresponding to the information received on said interferingsub-carriers by neutral soft bits having a magnitude equal to zero.

Thus, such a neutral soft bit will be considered having a very lowreliability which will be taken into account into the decoding step. Theinterference coming from the auxiliary device is thus minimised.

According to an embodiment of the invention, the detecting step of themain interference reduction mode comprises analysing a channel stepinformation and detecting the operation of said at lest one auxiliarydevice from said channel state information. Such channel stateinformation can be delivered for example by a channel estimatorgenerally incorporated in the wireless apparatus.

However, the detecting step preferably further comprises checking saidoperation detection by using a set of stored interference informationrespectively associated to a set of several different auxiliary devices.

In other words, in order to optimise the notching process according tothe invention, the spectral properties of the potential victim device(the auxiliary device) can be taken into account in the definitionprocess of the bits to be mapped into the reference symbol. Usually,only a limited amount of possible devices can be assumed as victimdevices in the corresponding transmission band of the main device. Thesedevices (e.g. WIMAX devices) are well defined and thus the band widthand the potential carrier frequencies in use are well known. By usingthis information, it is much easier to define the sub-carriers to benotched out based on the channel state information. By using this aposteriori knowledge, notching groups can be predefined and easily setup. For example, a sub-carrier group of 5 or 7 sub-carriers can bedefined for a WIMAX device with a band width of 20 MHz. The requirementson the frequency domain channel state information can thus be relaxed.

The main interference reduction mode advantageously comprises regularlychecking the operation of said auxiliary device and if said auxiliarydevice is no more detectable, the main interference reduction modeconcerning said no more detectable auxiliary device is stopped.

According to a variant of the invention, the main device and said atleast one auxiliary device are all together incorporated within a singlewireless communication apparatus. Thus, with such an embodiment, it ispossible to have the simultaneous operation of two different airinterfaces within a single wireless apparatus, for example a singlemobile terminal, while the mutual interferences are minimised if noteliminated.

With such a collocation variant, an indication of said group of at leastone sub-carrier having frequency interfering with said auxiliary band offrequencies of said auxiliary device, is advantageously stored withinsaid apparatus and said detecting step of the main interferencereduction mode comprises advantageously receiving from said auxiliarydevice an auxiliary control information representative of the operationor of the non-operation of said auxiliary device such that said maininterference reduction mode is performed only during the operation ofsaid auxiliary device.

Several different auxiliary devices may be respectively adapted to emitand/or receive information within several different auxiliary bands offrequency, each auxiliary band being narrower than said main band andincluded within said main band. In such a case, said main interferencereduction mode may be performed for at least some of said severaldifferent auxiliary devices.

Another possibility exists according to the invention for mitigating theinterferences between the main wide band device and the narrow bandinterferer. More precisely, according to an embodiment of the invention,the method comprises an additional interference reduction mode forreducing the interference between said main device and said at least onauxiliary device. Said additional interference reduction mode isperformed within said main device and includes:

-   -   detecting an emission from and/or a reception performed by said        at least one auxiliary device,    -   determining from said detection step a group of at least one        sub-carrier having frequencies interfering with said auxiliary        band of frequencies, and    -   shifting at least a part of said main band of frequencies        including said group with a chosen frequency shift.

Of course, the man skilled in the art will adapt said frequency shiftsuch that, after shifting, the shifted part remains within the limits ofsaid main band while being compatible with the non-shifted part of themain band of frequencies.

The frequency shift is for example at least equal to the width of thefrequency band of said at least one auxiliary device.

When the main band of frequencies is subdivided into several differentmutually spaced sub-bands, the shifting step comprises shifting at leastthe sub-band which contains at least a part of said group of interferingsub-carriers.

As for the notching variant of the invention, said detecting step of theadditional interference reduction mode (the shifting variant) comprisesfor example analysing a channel state information and detecting theoperation of said at least one auxiliary device from said channel stateinformation, and preferably checking said operation detection by using aset of stored interference information respectively associated to a setof several different auxiliary devices.

Said additional interference reduction mode may also comprise regularlychecking the operation of said auxiliary device and if said auxiliarydevice is no more detectable, said additional interference reductionmode concerning said no more detectable auxiliary device is stopped.

When said at least one auxiliary device and said main device are alltogether incorporated within a single wireless communication apparatus,the detecting step of the additional interference reduction modecomprises advantageously, as for the main interference reduction mode,the reception from said auxiliary device of an additional controlinformation representative of the operation or of the non-operation ofsaid auxiliary device such that said additional interference reductionmode is performed only during the operation of said auxiliary device.

Depending on the location of the auxiliary frequency band within themain band of frequencies, either the main interference reduction mode(notching mode) or the additional interference reduction mode (shiftingmode) can be selected.

It is also possible that both main interference reduction mode andadditional interference reduction mode are performed for a sameauxiliary device. For example, a shifting of a part (for example asub-band) of the main band of frequencies can be performed to eliminatethe interferences carried by some sub-carriers whereas the notchingoption is performed for the remaining interfering sub-carriers which arestill within said main band of frequency after the shifting step.

It is also possible that main interference reduction mode and additionalinterference reduction mode be respectively performed for differentauxiliary devices.

The main device can belong to a multi-carrier based Ultra Wide BandCommunication system, for example but not exclusively, an OFDM basedUltra Wide Band Communication system.

Said at least one auxiliary device may belong to a fix wireless system(FWA, fixed wireless access) like a WIMAX system. However, it is alsopossible that such an auxiliary device belongs to a mobile radio systemdefined by a mobile radio standard like for example UMTS, GSM, CDMA,EDGE, beyond IMT-2000 systems, or to a fixed satellite system (FSS), ifthe frequency band of the mobile radio system or the satellite system islocated within the main frequency band of the main device.

According to another aspect of the invention, it is also proposed awireless communication apparatus comprising a main device having a maintransmission chain including:

-   -   puncturing means for delivering a punctured stream of bits,    -   mapping means for delivering symbols from said punctured stream        of bits in accordance with a modulation mapping scheme,    -   a transmission stage for transmitting information issued from        said symbols on sub-carriers having frequencies belonging to a        main band of frequencies.

Said main device further includes main reduction interference means forreducing the interferences generated by said main device toward at leastone auxiliary device adapted to emit and/or receive information withinauxiliary band of frequencies, said auxiliary band being narrower thansaid main band and included within said main band.

Said main interference reduction means includes

-   -   main detection means for detecting an emission from and/or a        reception performed by said auxiliary device,    -   a main control unit connected to the main detection means for        determining a group of at least one sub-carrier having frequency        interfering with said auxiliary band of frequencies and        determining the bits of said punctured stream which correspond        to the information carried by said interfering sub-carriers of        said group, and    -   a main processing unit for processing said determined bits such        that said mapping means are adapted to map said processed bits        into a reference symbol having an amplitude equal or close to        zero.

According to an embodiment of the invention, said main processing unitis adapted to associate a control indication to each determined bits,and said mapping means are adapted to map the bits associated with saidcontrol indication into said reference symbol.

According to an embodiment of the invention, said main processing unitis adapted to associate a control bit to each bit of said puncturedstream, said control bit having a first logical value corresponding tosaid control indication, or a second logical value, and the mappingmeans are adapted to map the bits associated with said control bitshaving said second logical value into their corresponding symbols inaccordance with said modulation scheme.

According to an embodiment of the invention, said main device furthercomprises a reception chain including

-   -   a receiving stage for receiving information carried by said        sub-carriers and delivering received symbols from said received        information,    -   demapping means for demapping the received symbols according to        said modulation scheme and delivering a punctured stream of soft        bits, each soft bit having a sign representative of the        estimation of logical value of the corresponding bit and a        magnitude representative of the confidence in said estimation.

Said main device further comprises auxiliary interference reductionmeans for reducing the interference generated by said auxiliary devicetowards said main device, said auxiliary interference reduction meansincluding an auxiliary processing unit for replacing the soft bitscorresponding to the information received on said interferingsub-carriers by neutral soft bits having a magnitude equal to zero.

According to an embodiment of the invention, the apparatus furthercomprises a channel estimation unit adapted to deliver a channel stateinformation and said main detection means comprises main analysing meansfor analysing said channel state information and detecting the operationof said at least one auxiliary device from said channel stateinformation.

The apparatus may further comprise main memory means for storing a setof interference information respectively associated to a set of severaldifferent auxiliary devices, and main checking means for checking saidoperation detection by using said stored set of interferenceinformation.

The apparatus may also further comprise a main management unit adaptedto manage the operation of said main interference reduction means andsaid main interference reduction means are further adapted to regularlycheck the operation of said auxiliary device and if said auxiliarydevice is no more detectable said main management unit is adapted tostop the interference reduction concerning said no more detectableauxiliary device.

The apparatus may incorporate said main device and said at least oneauxiliary device all together.

In such a case, the apparatus may further comprise a main managementunit adapted to manage the operation of said main interference reductionmeans and auxiliary memory means for storing an indication of said groupof at least one sub-carrier having frequencies interfering with saidauxiliary band of frequencies of said auxiliary device. And saidauxiliary device comprises auxiliary control means for delivering anauxiliary control information representative of the operation or of thenon operation of said auxiliary device such that said main managementunit is adapted to allow the operation of said main interferencereduction means only during the operation of said auxiliary device.

According to an embodiment of the invention, several different auxiliarydevices are respectively adapted to emit and/or receive informationwithin several different auxiliary bands of frequencies, each auxiliaryband being narrower than said main band and included within said mainband, and said main interference reduction means are adapted to reducethe interference generated by said main device towards at least some ofsaid several different auxiliary devices.

According to another variant of the invention, the apparatus furthercomprises additional interference reduction means for reducing theinterference between said main device and said at least one auxiliarydevice, said additional interference reduction means including

-   -   additional detecting means for detecting an emission from and/or        a reception performed by said at least one auxiliary device,    -   an additional control unit connected to said additional        detecting means for determining a group of at least one        sub-carrier having frequencies interfering with said auxiliary        band of frequencies, and for shifting at least a part of said        main band of frequencies including said group, with a chosen        frequency shift.

When the main band of frequencies is subdivided into several differentmutually spaced sub-bands, the additional control unit is adapted toshift at least the sub-band which contains at least a part of said groupof interfering sub-carriers.

According to an embodiment of the invention, the apparatus furthercomprises a channel estimation unit adapted to deliver a channel stateinformation, and said additional detection means comprises additionalanalysing means for analysing said channel state information anddetecting the operation of said at least one auxiliary device from saidchannel state information. Additional memory means may be provided forstoring a set of interference information respectively associated to aset of several different auxiliary devices, and additional checkingmeans may check said operation detection by using said stored set ofinterference information. An additional management unit may be providedfor managing the operation of said additional interference reductionmeans. Said additional interference reduction means may be furtheradapted to regularly check the operation of said auxiliary device and ifsaid auxiliary device is no more detectable said additional managementunit is adapted to stop the interference reduction concerning said nomore detectable auxiliary device.

When said main device and said at least one auxiliary device are alltogether incorporated within a single wireless communication apparatus,the apparatus comprises, according to an embodiment of the invention, anadditional management unit adapted to manage the operation of saidadditional interference reduction means and additional memory means forstoring an indication of said group of at least one sub-carrier havingfrequencies interfering with said auxiliary band of frequencies of saidauxiliary device. Said auxiliary device comprises auxiliary controlmeans for delivering an auxiliary control information representative ofthe operation or of the non operation of said auxiliary device such thatsaid additional management unit is adapted to allow the operation ofsaid main interference reduction means only during the operation of saidauxiliary device.

Both said main interference reduction means and additional interferencereduction means may be adapted to perform their respective interferencereduction for a same auxiliary device or for different auxiliarydevices, respectively. Both main and additional detecting means may beidentical as well as both main and additional control units.

Other advantages and features of the invention will appear on examiningthe detailed description of embodiments, these being in no way limiting,and of the appended drawings in which:

FIG. 1 illustrates diagrammatically the internal protocol structure of awireless communication apparatus according to an embodiment of theinvention,

FIG. 2 illustrates a first embodiment of a method according to theinvention,

FIG. 3 illustrates more in details but still diagrammatically aninternal structure of a wireless communication apparatus according tothe invention,

FIGS. 4-7 illustrate diagrammatically flow charts related to anembodiment of a method according to the invention,

FIG. 8 illustrates diagrammatically another part of an internalstructure of an embodiment of a wireless communication apparatusaccording to the invention,

FIG. 9 illustrates a flow chart related to another embodiment of amethod according to the invention,

FIG. 10 illustrates diagrammatically another embodiment of a wirelesscommunication apparatus according to the invention,

FIG. 11 illustrates another embodiment of a method according to theinvention,

FIG. 12 illustrates diagrammatically another embodiment of an internalstructure of an embodiment of a wireless communication apparatusaccording to the invention, and

FIGS. 13 and 14 illustrate other flow charts related to anotherembodiment of a method according to the invention.

FIG. 1 discloses an example of a wireless communication apparatus WAPbelonging to a non-coordinated communication system such as a WLAN(“Wireless Local Area Network”) or a WPAN (“Wireless Personal AreaNetwork”).

Such a wireless apparatus WAP belongs for example to an OFDM based UltraWide Band Communication system. However, the invention is not limited tosuch an example and can apply more generally to generalisedmulti-carrier (GMC) systems in which the carriers are not necessarilyorthogonal.

WPAN MAC protocols have a distributed nature where there is no centralcoordinator terminal or base station to assign the medium access. There,in contrast to a mobile radio terminal, a WPAN transceiver has muchhigher flexibility to allocate the transmission slot and formats. Theallocation of the communication resources is a distributed process. Theallocation to a specific time slot in the super frame can be modifiedfrom one superframe to the next. The controlling entity is the WPAN-MAClayer of the communicating terminals. The allocation is based on therequested data rate and the type of service to be transmitted.Furthermore, the available resources are taken into account in theallocation process. The MAC layer requests a reservation for a specifictime slot or a number of time slots based on these constraints. Theseconstraints can be split into local constraints, like the data rate tobe transmitted or received and network wide constraints like the alreadyexisting slot reservation.

An example of distributed WPAN-MAC is MBOA MAC.

The proposed MBOA MAC standard draft is based on a UWB technology and isplaned to be used in the frequency band between 3.1 and 10.7 GHz. Firstimplementations using the standard work in the frequency range between3.1 GHz and 5.0 GHz.

The wireless apparatus WAP comprises a main device MDVC including anOFDM based UWB communication interface MCINT connected between the UWBapplication block MBLC and the air channel.

This communication interface MCINT comprises an UWB MAC layer clocked bya clock signal MCLK and connected to the PHY layer and to the UWBapplication block MBLC.

For further details concerning the MAC layer and the PHY layer of thecommunication interface MCINT, the man skilled in the art may refer toMBOA PHY layer Technical Specification, Version 1.0, January 2005, andto MBOA MAC layer Technical Specification, Version 0v7, October 2004.

The MAC layer manages in particular the emission/reception of the UWBdata stream and is incorporated by software in a control processor.

In FIG. 2 it can be seen that the main band of frequencies used for theoperation (transmission and/or reception) of the main device MDVC liesbetween 3.1 GHz and 4.9 GHz. Further, the main frequency band issubdivided into three sub-bands SB1, SB2, SB3, called hopping sub-bands,which are mutually spaced. More precisely, there is a guard interval of100 MHz between the lower limit (3.1 GHz) of the main frequency band andthe beginning of the first sub-band SB1 as well as between the end ofthe third sub-band SB3 and the upper limit (4.9 GHz) of the mainfrequency band.

Further, two adjacent sub-bands are spaced by a guard interval of 50MHz.

The allocation of the sub-bands during the transmission is madeaccording to a predetermined hopping sequence.

In the upper part of FIG. 2, a narrow band device (auxiliary device)XDVC is assumed to operate in an auxiliary band of frequencies includedwithin the second sub-band SB2. This auxiliary band of frequencies has awidth of 20 MHz.

Compared to a UWB device based on techniques like MBOA standard, such adevice XDVC is considered as being a narrowband device.

According to an aspect of the invention, which will be described more indetails thereafter, based on the control of the transmission chain ofthe UWB main device MDVC, the frequencies used by the narrowband deviceare not used for the transmission of the UWB signal. The correspondingsub-carriers in hopping sub-band 2 are not used, i.e. are notched out sothat the interferences generated by the main UWB device MDVC toward theauxiliary device XDVC are greatly reduced if not eliminated.

Since the narrowband device only uses a very small portion of the UWBspectrum for its transmission, the sub-carrier notching can be donewithout a severe influence to the communication performance of the UWBdevice MDVC.

In order to reduce these interferences by using such a notching process,the main device MDVC of the wireless communication apparatus WAPcomprises main interference reduction means MIFRM cooperating with thetransmission chain TXCH of the main device (FIG. 3).

In a conventional manner, the transmission chain TXCH comprises an outertransmission block OUTX including an encoder CC, for example aconvolutional encoder, receiving data from source coding means anddelivering a bits stream to puncturing means PM which delivers apunctured bits stream.

The other conventional means of the transmission chain TXCH areinterleaving means, ILM, followed by mapping means MPM which map thebits into symbols according to a modulation mapping scheme depending onthe kind of used modulation, for example a BPSK modulation or moregenerally a QAM modulation. The symbols are then delivered to an OFDMmodulator OFM which performs IFFT processing in order to associate eachsymbol to a sub-carrier and to form OFDM symbols. Each sub-carrier ismodulated in accordance with the value of the corresponding symbol.

The OFDM symbols are then processed in a conventional radio frequencystage RF before being transmitted on air through antenna ANT.

The mapping means MPM as well as the OFDM modulator OFM belong to aninner transmission block INTX of the transmission stage.

The operation of the main interference reduction means MIFRM which aredepicted in FIG. 3 will be now described with reference to this FIG. 3,FIG. 4 which depicts the main interference reduction mode MIRM and alsoto FIGS. 5-7.

A conventional channel estimation unit CHST delivers a channel stateinformation in the frequency domain. For example, this channel stateinformation is an impulse response of the channel and contains forexample, energy peaks at some frequencies. Main detection means DTMcomprises main analysing means AM for analysing said channel stateinformation and detecting the operation of the auxiliary device XDVC(step 40 in FIG. 4).

Although it is not compulsory, it is preferable that the eventualoperation of the WIMAX device detected by the analysing step 51 of thechannel state information (FIG. 5) be checked (step 52, FIG. 5) by meanchecking means MCKM connected to main memory means MM.

These main memory means MM contain a set of stored interferenceinformation, in particular the interference information related to theauxiliary device XDVC.

As a matter of fact, only a limited amount of possible devices can beassumed as victim devices in the corresponding main transmission band ofthe main device. These auxiliary devices are well defined and thus aband width and the potential carrier frequencies in use are well known.These information are stored in the main memory means.

Using this a posteriori knowledge notching groups can be predefined andeasily set up.

A main control unit MCU connected to the main detection means, is ableto determine a group of interference sub-carriers, for example from theanalysing of the channel state information. And, these interferingsub-carriers can be validated by the result of the checking operationperformed by main checking means MCKM in accordance with the content ofthe main memory means MM.

More precisely, for example, if the group of interference sub-carriersdetermined by the main control unit MCU by using the information givenby the main detection means DTM, corresponds to pre-stored interferingfrequencies, thus, there is a high probability that the informationgiven by the main detection means actually corresponds to a well-definedauxiliary device, and not, for example, to noise on the air channel.

The main control unit MCU will then determine the bits of the puncturedstream of bits which correspond to the information carried by saidinterfering sub-carriers of said group.

As a matter of fact, the symbol mappings on the sub-carriers and theinterleaver structure is a fixed value parameter in the standard for agiven transmission mode. Thus, it can be stored as a fixed value andneeds not to be recalculated. In other words, there is a one-to-onemapping (one-to-one correspondence) between a bit of the punctured bitsstream and a sub-carrier in the OFDM symbol.

Thus, the determined bits corresponding to the interfering sub-carriersto be notched out, are processed in a main process unit MPU connected tothe main control unit MCU and also connected between the main puncturingmeans PM and the interleaving means ILM.

More precisely, the processing step 43, (performed after the determiningstep 42) comprises associating a control bit cbt having a first logicalvalue (for example value 1) to each determined bit and associating acontrol bit cbt having a second logical value (for example 0 value) toeach other bits (steps 70 et 71, FIG. 7).

After interleaving, the bits are mapped into symbols in accordance withthe chosen modulation. The bits which are associated with a control bithaving the second logical value are mapped into their correspondingsymbols according to the modulation mapping scheme (step 73, FIG. 7).

The bits determined during the determining step 42, which are associatedwith the control bit having the first logical value, are mapped into areference symbol (step 44, FIG. 4 and step 73, FIG. 7).

This reference symbol has an amplitude equal or close to zero.

After OFDM modulation, each sub-carrier is modulated in accordance withthe value of the corresponding symbol. Thus, if the reference symbol hasan amplitude equal or close to zero, no information or almost noinformation will be transmitted by this sub-carrier. In other words, theenergy associated with this sub-carrier will be nul or almost nul. Thus,this sub-carrier is in fact notched out and no interference occursbetween the main device and the auxiliary device.

Instead of using only one reference symbol, it is possible to choose areference symbol into a set of possible reference symbols, for examplefour reference symbols. The corresponding sub-carriers could then becontrolled in their transmit power. The lowest value would completelynotch out the carrier whereas the higher values would only attenuate therelated sub-carrier. By doing so, some part of the cancelled informationcan be transmitted and thus a slight improvement of the communicationperformance could be reached. For example, the highest value of thereference symbol could be some percent (for example up to 2%) of thesmallest amplitude of the normal symbols (the conventional symbolscorresponding to the chosen modulation).

In order, in particular, to improve the operation of the main device, itis preferable that the operation of the auxiliary device XDVC beregularly checked (step 61, FIG. 6). If the auxiliary device is no moredetectable (step 62) then, the main interference reduction mode isstopped (step 63).

In this respect, the wireless communication apparatus WAP furthercomprises a main management unit MMU adapted to manage the operation ofthe main interference reduction means MIFRM and to stop eventually theiroperation.

The main interference reduction means MIFRM may be for exampleimplemented in the PHY layer of the main device. The main managementunit MMU may also be implemented in the PHY layer although it would bealso possible that this main management unit be implemented by softwarein the MAC layer.

Generally speaking, the main control unit, the main checking means, thedetection means and the main processing unit of the main interferencereduction means may be realised by software within a control processorand/or by hardware.

With this aspect of the invention, the block sizes of the bit stream tobe handled are constant with and without the processing step 43. Thus,no major changes are needed in the following processing unit(interleaver, mapper and OFDM modulator).

Further, no interaction in the transmission of the useful data isnecessary to inform the receiver and no change in the MAC layer protocolis needed.

The MBOA standard needs only small changes in the physical layer PHY.

Devices using this aspect of the invention can communicate with devicesnot using this aspect of the invention. Thus a smooth introduction ofthe method according to this aspect of the invention with a backwardcompatibility can be supported.

The method according to this aspect of the invention can easily becombined with other mitigation techniques like power control andadaptive sub-carrier loading.

Only the UWB device that is interfering with the victim device canoperate in the notching mode. For example, in a WIMAX system the homeequipment is the only WIMAX device which can see the interference from aUWB device in the home. The uplink receiver at the base station is tofar away from the UWB device to see any interference generated by thedevice. Thus it is not needed to notch out the correspondingsub-carriers in the complete UWB piconet but only at the device closestto the potential victim receiver. The communication performance of allother devices is not influenced at all.

As depicted in FIG. 8, the main device MDVC of the wirelesscommunication apparatus WAP further comprises a reception chain RXCHincluding a receiving stage for receiving information carried by thesub-carriers and delivering received symbols from said receivedinformation. The receiving stage includes in particular a radiofrequency stage RF connected to the antenna ANT followed by a OFDMdemodulator DOFM (FFT processing).

The reception chain contains also demapping means DMPM for demapping thereceived symbols according to the modulation scheme and delivering apunctured stream of soft bits to deinterleaver means DILM.

A soft bit, for example a Log-Likelihood Ratio LLR, well-known by theman skilled in the art, has a sign representative of the estimation ofthe logical value (0 or 1) of the corresponding bit and a magnituderepresentative of the confidence in said estimation. Thus, a soft bit,which is coded on several hard bits may have theoretically a valuecomprised between −∞ and +∞. And, the higher the magnitude is, thehigher the confidence in the estimation is.

The main device further comprises auxiliary interference reduction meansAUXIFRM for reducing the interference generated by the auxiliary devicetowards the main device.

The auxiliary interference reduction means AUXIFRM includes, as depictedin FIG. 8, an auxiliary processing unit XCU for replacing the soft bitscorresponding to the information received on said interferingsub-carriers by neural soft bits having a magnitude equal to zero.

This operation is more detailed in FIG. 9 which depicts he main steps ofthe auxiliary interference reduction mode XIRM.

More precisely, after receiving information carried by interferingsub-carriers (step 90) an OFDM demodulation 91 is performed. Thereceived symbols are then demapped (step 92) and the corresponding softbits are replaced by neutral soft bits 93.

Thus, after depuncturing in depuncturing means DPM, the bits are decodedin a decoder DCC. And, the neutral soft bits are considered as beingnoise or information with a very low reliability. Thus, these data arecorrected in the decoding process. Accordingly, the interferencesgenerated by the auxiliary device are minimised if not eliminated.

As illustrated in FIG. 10, it is possible that the wirelesscommunication apparatus WAP incorporates both main device MDVC andauxiliary device XDVC.

In such a case, the MAC layer of the auxiliary device XDVC is able todeliver to the main management unit contained in the MAC layer of themain device MDVC an auxiliary control information XCLI representative ofthe operation or of the non-operation of the auxiliary device such thatsaid main management unit is adapted to allow the operation of the maininterference reduction means only during the operation of said auxiliarydevice.

Further, it is no more necessary to analyse the channel stateinformation. As a matter of fact, the group of interfering sub-carriersis well known for this auxiliary device and pre-stored in the mainmemory means of the main device.

Such an implementation of the invention will allow for the simultaneousoperation of for example a WIMAX or a mobile radio and WPAN UWB airinterface in a single mobile terminal. The mutual interference will beminimised if not eliminated. The overall WPAN network will not beinfluenced by the frequency domain coordinated transmission andreception of the co-located WPAN device. The coordinated transmissionand reception of the slave WPAN air interface might lead to a reductionof the maximum reachable data rate and/or the reliability of the link.Thus might lead to a reduction in reach of the link.

Another solution exists for reducing the interferences generated betweenthe main device and the auxiliary device. This other solution, based ona frequency shifting, will now explain more in details with reference toFIGS. 11 to 14.

More precisely, in the example depicted in FIG. 11, the interferencereduction is controlled by changing the carrier frequencies of thehopping sub-bands by moving the two lower bands slightly low in thefrequency domain.

As a matter of fact, the narrowband interferer XDVC lies here near theend of the second sub-band SB2. Thus, by shifting the sub-band SB1 witha shift of 100 MHz towards the low frequencies and by shifting sub-bandSB2 with a shift of 150 MHz towards the low frequencies, the narrowbandinterferer XDVC lies now between sub-band SB2 and sub-band SB3.

Of course, the man skilled in the art will choose the frequency shift bytaking into account the guard intervals of the MBOA hopping sub-bands.

As illustrated in FIG. 12, in order to perform this controlled frequencyshift, the main device MDVC of the wireless communication apparatus WAPcomprises additional interference reduction means ADIFRM for reducingthe interference between the main device and auxiliary device. It can benoted that according to this variant of the invention, the frequencyshifting permits to minimise, if not eliminate, the interferencegenerated by the main device MDVC towards the auxiliary device XDVC butalso the interference generated by the auxiliary device XDVC towards themain device MDVC.

As for the main interference reduction means, the additionalinterference reduction means ADIFRM includes additional detecting meansADTM for detecting an emission from and/or reception performed by theauxiliary device. An additional control unit ADCU is provided fordetermining the group of the interfering sub-carriers, and for shiftingat least a part of said main band of frequencies including said group ofinterfering sub-carriers, with a chosen frequency shift.

And this frequency shifting is obtained for example by controlling thetransposition frequency of the mixers contained in the radio frequencystage RF.

The additional interference reduction mode ADIRM, performed by theadditional interference reduction means ADIFRM is depicteddiagrammatically on FIGS. 13 and 14. More precisely, after havingdetected the operation of the WIMAX device (step 130), the interferingsub-carriers are determined (step 131) and the frequencies band isshifted (step 132), for example by a sub-band shifting 140 (FIG. 14).

Of course it is necessary to indicate this frequency shift to all thedevices of the UWB network which are in communication with said maindevice. This is performed for example by sending control information tothese devices. This control information can be sent for example by theMAC layer of the main device through control channels.

Further, as for the main interference reduction means, the additionalinterference reduction means ADIFRM comprises also additional analysingmeans ADAM for analysing the channel state information delivered by thechannel estimator, additional checking means ADCKM for checking theeventual detection of the operation of the auxiliary device by usinginformation about the interferers, pre-stored in additional memory ADMM.

Further, an additional memory management unit ADMU manages the operationof the additional interference reduction means ADIFRM and in particularstops the operation thereof when the auxiliary device is no moredetectable.

In a preferred embodiment, both main and additional detection means areidentical as well as both main and additional control units and bothmain and additional management units.

The sub-band shifting does not reduce the available resources on theair. The data rate needs not to be reduced. Thus no loss ofcommunication performance accurse.

Of course, both main interference reduction mode (notching mode) andadditional interference reduction mode (shifting mode) can be performedfor a same auxiliary device. This is the case in particular when thenarrowband interferer is far enough from the end of a sub-band so that asole frequency shifting is not enough for eliminating all theinterfering sub-carriers. In such a case, the remaining interferingsub-carriers can be notched out by using the main interference reductionmode.

Although the invention has been described with an auxiliary device beinga WIMAX device, such an auxiliary device could belong to a mobile radiosystem defined by a mobile radio standard, like for the example GSM,UMTS, CDMA, EDGE or future beyond IMT-2000 systems under development. Anauxiliary device could be a fixed satellite service (FSS) device or ageneral fixed wireless access device (FWA).

For an UMTS mobile radio device collocated with an UWB main device, theauxiliary control means which delivers the indication of the operationof the UMTS device can be incorporated in or connected to the well-knownL2 and L3 entities of the UMTS device (This is valid for the collocationin general. The UWB device could be collocated with a Wimax terminal, asatellite terminal or another mobile radio terminal.)

1-52. (canceled)
 53. A method for reducing interference between a maindevice that transmits information on sub-carriers having frequenciesbelonging to a main band of frequencies, the information based uponsymbols obtained by a mapping of a punctured stream of bits according toa modulation mapping scheme, and at least one auxiliary device that atleast one of emits and receives information within an auxiliary band offrequencies, the auxiliary band of frequencies being narrower than themain band and included within the main band, the method comprising:performing a main interference reduction mode within the main device andcomprising a detection step for detecting at least one of an emissionfrom and a reception performed by the at least one auxiliary device;determining from the detection step at least one interfering sub-carrierinterfering with the auxiliary band of frequencies; determining bits ofthe punctured stream of bits which correspond to the information carriedby the at least one interfering sub-carrier; and processing thedetermined bits to generate processed bits mapped to a reference symbolhaving an amplitude within a threshold of zero.
 54. A method accordingto claim 53, wherein the detection step is to detect an emission fromand a reception performed by the at least one auxiliary device.
 55. Amethod according to claim 53, wherein the processed bits are mapped to areference symbol having an amplitude equal or close to zero.
 56. Amethod according to claim 53, wherein the reference symbol is chosenwithin a group of several reference symbols having respectivelydifferent amplitudes, each amplitude within a threshold of zero.
 57. Amethod according to claim 53, wherein a control indication is associatedto each determined bit; and wherein bits associated with the controlindication are mapped to the reference symbol.
 58. A method according toclaim 57, wherein processing the determined bits comprises associating acontrol bit to each bit of the punctured stream of bits, the control bithaving either a first logical value corresponding to the controlindication or a second logical value, the bits associated with thecontrol bits having the second logical value being mapped tocorresponding symbols in accordance with the modulation mapping scheme.59. A method according to claim 53, wherein the main device is also toreceive information carried by the sub-carriers and to perform areception processing comprising determining received symbols frominformation received and a demapping of the received symbols forproviding a punctured stream of soft bits, each soft bit having a signrepresentative of an estimation of a logical value of a correspondingbit and a magnitude representative of a confidence in the estimation,the method further comprising further reducing interference generated byat least one auxiliary device towards the main device, the furtherreducing being performed within the main device and including replacingthe soft bits corresponding to the information received on theinterfering sub-carriers by neutral soft bits having a magnitude withina threshold of zero.
 60. A method according to claim 53, wherein thedetection step of the main interference reduction mode comprisesanalyzing channel state information and detecting operation of the atleast one auxiliary device from the channel state information.
 61. Amethod according to claim 60, wherein the detection step furthercomprises checking the detecting by using a set of stored interferenceinformation respectively associated to a set of several differentauxiliary devices.
 62. A method according to claim 53, wherein the maininterference reduction mode comprises regularly checking operation ofthe at least one auxiliary device and if the at least one auxiliarydevice is not detectable, the main interference reduction modeconcerning the at least one auxiliary device is stopped.
 63. A methodaccording to claim 53, wherein the main device and the at least oneauxiliary device are incorporated together within a single wirelesscommunication apparatus.
 64. A method according to claim 63, wherein anindication of the at least one interfering sub-carrier of the at leastone auxiliary device is stored within the single wireless communicationapparatus and the detection step of the main interference reduction modecomprises receiving from the at least one auxiliary device auxiliarycontrol information representative of operation or non-operation of theat least one auxiliary device, the main interference reduction mode tobe performed only during operation of the at least one auxiliary device.65. A method according to claim 53, wherein several different auxiliarydevices respectively at least one of emit and receive information withinseveral different auxiliary bands of frequencies, each auxiliary bandbeing narrower than the main band and within the main band; and whereinthe main interference reduction mode is performed for at least some ofthe several different auxiliary devices.
 66. A method according to claim53, further comprising performing an additional interference reductionmode to further reduce interference between the main device and the atleast one auxiliary device, the additional interference reduction modebeing performed within the main device and comprising further detectingat least one of an emission from and a reception performed by the atleast one auxiliary device, determining from the further detecting atleast one interfering sub-carrier interfering with the auxiliary band offrequencies, and shifting at least a part of the main band offrequencies including the at least one interfering sub-carrier with achosen frequency shift.
 67. A method according to claim 66, wherein thechosen frequency shift is at least equal to a width of a frequency bandof the at least one auxiliary device.
 68. A method according to claim66, wherein the main band of frequencies is subdivided into severaldifferent mutually spaced sub-bands, and the shifting comprises shiftingat least the sub-band which contains the at least one interferingsub-carrier.
 69. A method according to claim 66, wherein the furtherdetecting of the additional interference reduction mode comprisesanalyzing channel state information and operation detection fordetecting operation of the at least one auxiliary device from thechannel state information.
 70. A method according to claim 69, whereinthe further detecting further comprises checking the operation detectionby using a set of stored interference information respectivelyassociated to a set of several different auxiliary devices.
 71. A methodaccording to claim 66, wherein the additional interference reductionmode comprises regularly checking operation of the at least oneauxiliary device and if the at least one auxiliary device is notdetectable, the additional interference reduction mode concerning thenot detectable at least one auxiliary device is stopped.
 72. A methodaccording to claim 66, wherein the main device and the at least oneauxiliary device are incorporated together within a single wirelesscommunication apparatus.
 73. A method according to claim 72, wherein anindication of the at least one interfering sub-carrier of the at leastone auxiliary device is stored within the single wireless communicationapparatus and the further detecting of the additional interferencereduction mode comprises receiving from the at least one auxiliarydevice additional control information representative of operation ornon-operation of the at least one auxiliary device, the additionalinterference reduction mode being performed only during the operation ofthe at least one auxiliary device.
 74. A method according to claim 66,wherein both the main interference reduction mode and the additionalinterference reduction mode are performed for a same auxiliary device.75. A method according to claim 66, wherein the main interferencereduction mode and the additional interference reduction mode arerespectively performed for different auxiliary devices.
 76. A methodaccording to claim 53, wherein the main device belongs to amulti-carrier based Ultra Wide Band communication system.
 77. A methodaccording to claim 76, wherein the main device belongs to an OFDM basedUltra Wide Band communication system.
 78. A method according to claim53, wherein the at least one auxiliary device belongs to a fixedwireless access system, like a WIMAX system, or to a mobile radio systemdefined by a mobile radio standard, like GSM, UMTS, CDMA, and EDGE. 79.A method according to claim 53, wherein the at least one auxiliarydevice belongs to a fixed satellite service system.
 80. A wirelesscommunication apparatus comprising: a main device comprising a maintransmission chain including puncturing circuitry to deliver a puncturedstream of bits, mapping circuitry to map symbols from the puncturedstream of bits in accordance with a modulation scheme, a transmissionstage to transmit information issued from the symbols on sub-carriershaving frequencies belonging to a main band of frequencies, maininterference reduction circuitry to reduce interference generated by amain device toward at least one auxiliary device that at least one ofemits and receives auxiliary information within an auxiliary band offrequencies, the auxiliary band of frequencies being narrower than themain band of frequencies and included within the main band offrequencies, said main interference reduction circuitry comprising maindetection circuitry to detect at least one of an emission from and areception performed by the at least one auxiliary device, a main controlunit coupled to the main detection circuitry to determine at least oneinterfering sub-carrier interfering with the auxiliary band offrequencies and determining bits of the punctured stream of bits whichcorrespond to information carried by the at least one interferingsub-carrier, and a main processing unit to process determined bits andmap processed bits into a reference symbol having an amplitude within athreshold of zero.
 81. An apparatus according to claim 80 wherein saidmain processing unit is to process determined bits and map processedbits into a reference symbol having an amplitude equal or close to zero.82. An apparatus according to claim 80, wherein the reference symbol ischosen within a group of several reference symbols having respectivelydifferent amplitudes, each amplitude within a threshold of zero.
 83. Anapparatus according to claim 80, wherein the main processing unit is toassociate a control indication to each determined bit; and wherein themapping circuitry is to map bits associated with the control indicationinto the reference symbol.
 84. An apparatus according to claim 83,wherein the main processing unit is to associate a control bit to eachbit of the punctured stream of bits, the control bit having a firstlogical value corresponding to the control indication, or a secondlogical value; and wherein the mapping circuitry is to map bitsassociated with the control bits having the second logical value intotheir corresponding reference symbols in accordance with the modulationscheme.
 85. An apparatus according to claim 80, wherein the main devicefurther comprises a reception chain including a receiving stage toreceive information carried by the sub-carriers and to deliver receivedsymbols from the received information, demapping circuitry to demap thereceived symbols according to the modulation scheme and delivering apunctured stream of soft bits, each soft bit having a signrepresentative of an estimation of a logical value of a correspondingbit and a magnitude representative of confidence in the estimation, themain device further comprising auxiliary interference reductioncircuitry to reduce interference generated by the at least one auxiliarydevice toward the main device, the auxiliary interference reductioncircuitry including an auxiliary processing unit to replace soft bitscorresponding to information received on the at least one interferingsub-carrier by neutral soft bits having a magnitude equal to zero. 86.An apparatus according to claim 80, further comprising a channelestimation unit to deliver channel state information; and wherein themain detection circuitry comprises main analyzing circuitry to analyzechannel state information and detect operation of the at least oneauxiliary device from the channel state information.
 87. An apparatusaccording to claim 86, further comprising main memory circuitry to storea set of interference information respectively associated to a set ofseveral different auxiliary devices, and main checking circuitry tocheck the operation detection by using the stored set of interferenceinformation.
 88. An apparatus according to claim 80, further comprisinga main management unit to manage the operation of said main interferencereduction circuitry, wherein said main interference reduction circuitryregularly checks operation of the at least one auxiliary device and ifthe at least one auxiliary device is not detectable, the main managementunit is to stop reducing interferences concerning the not detectable atleast one auxiliary device.
 89. An apparatus according to claim 80,wherein the main device and the at least one auxiliary device areincorporated together in the wireless communication apparatus.
 90. Anapparatus according to claim 89, further comprising a main managementunit to manage operation of said main interference reduction circuitry,and auxiliary memory circuitry to store an indication of the at leastone interfering sub-carrier; and wherein the at least one auxiliarydevice comprises auxiliary control circuitry to deliver an auxiliarycontrol information representative of operation or non-operation of theat least one auxiliary device, the main management unit to allowoperation of said main interference reduction circuitry only during theoperation of the at least one auxiliary device.
 91. An apparatusaccording to claim 80, wherein several different auxiliary devicesrespectively at least one of emit and receive information within severaldifferent auxiliary bands of frequencies, each auxiliary band offrequencies being narrower than the main band of frequencies andincluded within the main band of frequencies; and wherein said maininterference reduction circuitry is to reduce interference generated bythe main device toward at least some of the several different auxiliarydevices.
 92. An apparatus according to claim 80, further comprisingadditional interference reduction circuitry to reduce interferencebetween the main device and the at least one auxiliary device, theadditional interference reduction circuitry including additionaldetecting circuitry to detect at least one of an emission from and areception performed by the at least one auxiliary device, an additionalcontrol unit coupled to the additional detecting circuitry to determineat least one interfering sub-carrier interfering with the auxiliary bandof frequencies, and to shift at least a part of the main band offrequencies including the at least one interfering sub-carrier with achosen frequency shift.
 93. An apparatus according to claim 92, whereinthe chosen frequency shift is at least equal to a width of a frequencyband of the at least one auxiliary device.
 94. An apparatus according toclaim 92, wherein the main band of frequencies is subdivided intoseveral different mutually spaced sub-bands, and the additional controlunit is to shift at least a sub-band which contains the at least oneinterfering sub-carrier.
 95. An apparatus according to claim 92, furthercomprising a channel estimation unit to deliver channel stateinformation; and wherein the additional detection circuitry comprisesadditional analyzing circuitry to analyze the channel state informationand detecting operation of the at least one auxiliary device from thechannel state information.
 96. An apparatus according to claim 95,further comprising additional memory circuitry to store a set ofinterference information respectively associated to a set of severaldifferent auxiliary devices, and additional checking circuitry to checkresults of the additional detection circuitry by using the stored set ofinterference information.
 97. An apparatus according to claim 92,further comprising an additional management unit to manage operation ofthe additional interference reduction circuitry; and wherein theadditional interference reduction circuitry is to regularly checkoperation of at least one auxiliary device and if the at least oneauxiliary device is not detectable the additional management unit is tostop reducing interference concerning the not detectable at least oneauxiliary device.
 98. An apparatus according to claim 92, wherein themain device and the at least one auxiliary device are incorporatedtogether within a single wireless communication apparatus.
 99. Anapparatus according to claim 98, further comprising an additionalmanagement unit to manage operation of the additional interferencereduction circuitry, and additional memory circuitry to store anindication of the at least one interfering sub-carrier of at least oneauxiliary device; and wherein the at least one auxiliary devicecomprises auxiliary control circuitry to deliver auxiliary controlinformation representative of operation or non-operation of the at leastone auxiliary device, the additional management unit to allow operationof said main interference reduction circuitry only during the operationof the at least one auxiliary device.
 100. An apparatus according toclaim 92, wherein both said main interference reduction circuitry andthe additional interference reduction circuitry are to perform theirrespective interference reduction for a same auxiliary device.
 101. Anapparatus according to claim 92, wherein said main interferencereduction circuitry and the additional interference reduction circuitryare to perform their respective interference reduction for differentauxiliary devices.
 102. An apparatus according to claim 92, wherein boththe main detection circuitry and additional detecting circuitry areidentical, and the main control unit and the additional control unit areidentical.
 103. An apparatus according claim 92, wherein the main devicebelongs to a multi-carrier based Ultra Wide Band communication system.104. An apparatus according to claim 103, wherein the main devicebelongs to an OFDM based Ultra Wide Band communication system.
 105. Anapparatus according to claim 103, wherein a physical layer of the maindevice incorporates each interference reduction circuitry.
 106. Anapparatus according to claim 80, wherein the at least one auxiliarydevice belongs to a fixed wireless access system, like a WIMAX system,or to a mobile radio system defined by at least one mobile radiostandard of GSM, UMTS, CDMA, and EDGE.
 107. An apparatus according toclaim 80, wherein the at least one auxiliary device belongs to a fixedsatellite service system.